John isaac watts and william armstrong richards



UNITED STATES PATENT rricn.

JOHN ISAA C W ATTS AND ILLIAM ARMSTRONG RICHARDS, OF SANDBACH, COUNTY OF CHESTER, ENGLAND.

SALT OF SODIUM.

SPECIFICATION forming part of Letters Patent No. 399,175, dated March 5, 1889.

Application filed July 5,

1887. Serial No 243,439, (No specimens) Patented in England October 12, 1886,1310. 13,001.

" all whom it may concern:

Be it known that we, JOHN Isaac WAT'Is and \VILLLUI Annsrnono RICHARDS, manufacturing chemists, subjects of the Queen of Great Britain, residing at Sandbach, in the county of hestcr, in the Kingdom of England, have invented a certain new and useful Improved Sodium Salt, (for which we have obtained provisional protection in England,

dated October 12, 1886, No. 13,00l,) of which the following is a specification.

This invention has for its object the production of a new article oi manufacture, which we call sesquicarbonate of soda, and

r 5 which is composeiil, mainly, of one equivalent ot bicarbonate of soda, one equirnlent of mo nocarbonate oi. soda, and two equivalents of water in chemical combination, (NznKQNn li( (),-2li,().)

sists in forming an aqueous solution containing three equivalents of soda to four (or between three and four) equivalents of carbonic acid, and crvstallizing' out at a tcnujleraturc not below ccntigrade. There are several different methods of obtaining the solution. *0 prefer to form it by treating; bicarljionate of soda in such manner as to deprive it of about one-third of its carbonic acid, or by 30 mixi n it in solution with a chemically-equiva lent quantit of monocarbonate of soda. lhe

Our method of mannfacturingthis salt conmonocarbonate can be a little in excess, but 1 not the bicarbonate, or the excess ot' bicarbonate will be found in the product.

In carrying the invention into practice we have found the following methods of preparing the solution all cheap and practicable. \Ve give them in the order in which we prefer them.

((0) \Yo heat bicarbonate of soda by any well-known means in such a manner as'to deprive it of abou t on ethird of its carbonic acid, and then dissolve the salt thus treated in hot water; (11) orto a solution oi". monocarbonato of soda we add the equivalent quantity of bicarbonate of soda-that is, about eighty-four parts of bicarbonate of soda are added to about every one hundred and six parts of inonocarbonate of soda; or we boil bicarbonate of soda with water until one-third of the can bonic acid is given 0ft; ((1) or we treat bicaroperations, instead of water.

bonate of soda with caustic alkali suiticientto form the requisite amount of inonocarbonate of soda to combine with the remaining bicarbonate oi soda in the proportion of about 5 5 one hundred and six parts of monocarliionate to eightyfour parts of bicarbonate; (e) or we treat bicarbonate of soda in solution with the oxide of any alkaline earth in sufficient quantity to combine with about one-third of 6c the carbonic acid present. Besides the alkaline earths there are other substances that will unite with carbonic acid that could be used for this purpose, but except in the rare case where it is desired to form a special carbonate in this way and obtain the sesmiicarbonato as a byproduct, they are too expensive for commercial use, so it is needless to enumerate them.

The solution obtaincdby anyol' these Ineth- 7o ods is clarified, it necessary, and slowly cooled, preferably while it islzept agitated, when. the sesquiearbonai'e crystallizes out; but the temperature of the solution must not be allowed to tall below o0 Centigrade, as below this temporature other carbonates of soda crystallize out from the liquor. It the solution obtained is not fully saturated, it can be concen trated by evaporation before submitting it to cnvstallization. Sodium chloride can be added to the solution to accelerate the crystallization, if desired.

In cases where sodium chloride is not added, the mothcit-liquor can be used in subsequent The scsqnicarbonate of soda is obtained in the form of distinct crystals and. can be separated from the mother-liquor and dried by filter-presses, hydro-extractors, or any other well-known means. 0

Having now particularly described and ascertained the nature of the said invention and in what manner the same is to be performed, wc declare that we are aware that a native crystalline substance has been found in an 9 5 impure form called sesquicarbonate of soda, and that ithas been known as a scientific fact that under certain circumstances a crystalline carbonate of soda has been formed differing from both sodium monocarbonate and 10a sodium bicarbonate in the proportions of carbonic acid and soda found therein; but these substances differ materially in chemical composition from the product manufactured by our process, for while, according to the best authorities, the substance which has hitherto 5 been known contains three equivalents of carbonic acid to two equivalents of soda our compound contains four equivalents of carbonic acid to three equivalents of soda. Our new compound therefore contains consider- 1o ably less bicarbonate of soda, and is consequently much more valuable for numerous industrial purposes. We have without hesitation given it commercially the same name, (sesquicarbonate of soda,) because the pro- I 5 duct previously prepared has never been made on a large scale, and is not now an article of commerce.

\Ve do not claim herein the method of 

